Fig. 2. Total leaf Zn (a) and Cu (b) concentrations after 35 days in maize plants in response to the addition of Zn doses (expressed as mg kg−1) in a vineyard soil contaminated with Cu.
Columns followed by the same letter in each crop show no statistically significant difference according to the Scott–Knott test (P b 0.05). Positive (+) and negative (−) signs indicate
higher and lower values for each Zn doses applied to vineyard soil compared to the reference soil according to the Mann–Whitney U-test (P b 0.05).